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1 . 2
  Keel Bolts and General Topics on Keel - Question re. 431/003 keel attachment
 
 
 
22 March 2016 - 00:37
#1
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
  Question re. 431/003 keel attachment  
 

 

Hello Forum, 

 

I have a question re. my keel attachment situation. In general I am not too concerned - but maybe sombody has experience to confirm that, or - worst case - rcommend action to be taken - Lars? :-)

When I bought the boat back in 1995, all the keel was covered with a GRP layer which did not stick very well on e lead, and required to be serviced all the time, during every winter season. About 10 years ago, I decided to have the GRP taken off. We gave the lead a filler and paint system and no GRP, which has workd fine. Virtually no movement and no slot or what ever between hull and keel, and not negative effects on the keel. 

At the aft face of the keel, about 5-10 cm above the keel joint, there seems to be a little damage on the GRP, looks like a little crack, about 2-4 cm long. See attachd photos. All you see is some salt crystals which develops during the winter season. 

This little damage had been there when I had bought the boat, and during the keel service I had asked the shipyard to reinfoce the GRP at the aft face of the keel. They did this, and the crack scenario has improved since. But it is still there. 

What do you think of this? What should I do? Should I just ignore this? Business colleagues (Swan dealership people) told me is is a normal thing, and I should ignore it. Would you agree? 

 

Best Regards

 

Christian

Chinook / 431-003

 
     
 
 
22 March 2016 - 00:39
#2
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

Black pictures. Wow. Try again ...

 
     
 

 
     
 

 
     
 

 
     
 
 
22 March 2016 - 14:42
#3
 
  the professor Join Date: 02 January 2008
Posts: 1148
 
 

Dear Christian

It is likely that this is an old grounding damage, the trailing edge radius suffers first.
The repair probably did not go deep enough if there still is cracking, but also the condition of the keel floors inside should be checked, damage will allow flexing.
Suggest you take photos also inside.
Kind regards
Lars
 
     
 
 
22 March 2016 - 23:33
#4
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

Dear Lars, 

 

many thanks for your quick and professional comment. I have no chance to take photos from the inside next weekend - bought my wife and myslf an Easter vacation in Venice :-) 

But I will take some photos the week after, will upload them in a good weeks' time. 

 

Best regards

Christian

Chinook - 431/003

 
     
 
 
24 March 2016 - 13:45
#5
 
  IHe Join Date: 06 January 2012
Posts: 46
 
 

Hi Christian, could You take a measurement r (=radius) of the rounding between the keel pocket and the bottom looking from either side of the Yacht? Even an approximate one. I could compare it to ours and tell if there's any difference. Our Yachts are from the same mould I suppose.

If You r is smaller than ours it could indicate that after a grounding long ago the broken GRP was grinded away --> making the radius smaller  --> some putty to smoothen it and the problem is optically solved. But after this repair the loads concentrate to that smaller area of the rounding and a new small crack could develope (as seen) during the normal sailing loads.

BR

IHe

CAID - Swan 431/12

 
     
 
 
24 March 2016 - 13:54
#6
 
  IHe Join Date: 06 January 2012
Posts: 46
 
 

Here's a picture from the measurement I mean.

 

IHe

 

CAID

 
     
 

 
     
 
 
25 March 2016 - 14:19
#7
 
  chinook Join Date: 17 March 2010
Posts: 48
 
 

Good idea IHe, thanks for the input! I will do that next Friday / Saturday, when I am on board again. 

 

Christian

 

 
     
 
 
30 March 2016 - 12:34
#8
 
  philippeV Join Date: 02 February 2007
Posts: 165
 
 

Dear all,

This is a matter which has been discussed in a previous thread, if I remember well.

We had this kind of problem repeatedly on Soeur Anne 41/022 until we decided to avoid putting wooden blocks supporting the boat on the dry (when we take her out each year) near the rear of the keel, i.e. near the trailing edge, as yards often do. This can create an important load  on a very thin part, espectially where lead meets the polyester.

To us the minimum distance is around 20 cm from the trailing edge.

If you respect this I bet you will have no more problems!!

Kind regards.

Philippe

 
     
 
 
31 March 2016 - 18:30
#9
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

Dear IHe, 

 

I took a pattern of the keel hull curve today, see below. The radius you referred to is very close to 105 mm. Intersted to hear what your boat has. 

 

Best Rgards

Christian 

Chinook // 431-003

 
     
 

 
     
 
 
31 March 2016 - 19:05
#10
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

Dear Lars, 

 

I took some photos today fom the inner keel hull joint aft, as you requested. Actually, the battery box sits on top of this area, and I tried to do this without removing the box. See below. In case you want me to remove it, I can do that, but maybe this is sufficient? I see a small crack, do you think this is essential? 

For you information, I repainted this area with the original brown gelcoat kind of paint, many years ago. Got it from Bruno, at that time. 

 

Best Regards

Christian

CHINOOK // 431-003

 
     
 

 
     
 

 
     
 
 
31 March 2016 - 19:15
#11
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

 

Hello philippeV, 

 

many thanks for your post. Actually, I think this is not part of the problem, see below for our typical keel support on land. 

 

Best Ragards

Christian

CHINOOK // 431-003

 
     
 

 
     
 
 
31 March 2016 - 19:47
#12
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

Lars, in case you require a higher resolution photo, give me an email address, or what ever. File size for the forum upload is limited. It says max. 4MB, but it seems I have no success in uploading a 1.4 MB photo. Christian

 
     
 

 
     
 
 
31 March 2016 - 19:53
#13
 
  matteosalamon Join Date: 29 January 2007
Posts: 638
 
 

Hi Christian,

please send me the photo and I will re-size it for you (photo must be under 4 mb when opened)

Fair winds!

matteo (47/069 Vanessa)

 
     
 
 
01 April 2016 - 06:54
#14
 
  IHe Join Date: 06 January 2012
Posts: 46
 
 

Hi Christian, I'm on a holiday right now and will be visiting the Yacht after a week. I'll send my measurements then.

 

IHe

431-12 CAID

 
     
 
 
01 April 2016 - 07:05
#15
 
  the professor Join Date: 02 January 2008
Posts: 1148
 
 

Dear Christian

Thank you for the photos.
The small crack indicates there has been some flexing, but not serious. Apparently there is a transverse floor just aft of this area - this is also the saloon aft bulkhead - how does the connection between this floor and bottom look?
And where is the next floor forward, and how does the same connection look?
Lars
 
     
 
 
03 April 2016 - 18:54
#16
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

 

Dear Lars, 

 

I took some photos from the inside of the aft keel area, as requested. 

Actually, the day was a bit of a frightening experinece altogether as, shortly after I arrived at the shipyard where CHINOOK ist in winter storage, I saw lots of firebrigade trucks arrive, and had the unpleasant experience to watch the whole shipyard burn down. I was lucky, CHINOOK and the hall where she is stored are OK, and even the mast is OK, although the fire got so close that there was only a 3m distance left between fire and mast. 4 yachts totally lost though, and I don't know yet how many masts. Wow, the nightmare of 40 years sail yacht ownership was never so close to reality as yesterday. 

Anyway, I think the photos show a good situation. All in good shape and exactly as I remembered it. See below. Any questions, just get back to me. Interested to hear what you think. 

 

Christian

CHINOOK // 431-003

 
     
 

Good news. The small crack seen is not a crack, was just dirt.
 
     
 

Portside forward frame
 
     
 

Portside aft frame
 
     
 
 
03 April 2016 - 18:58
#17
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 
 
     
 

Starboard frame forward
 
     
 

Starboard frame aft
 
     
 
 
03 April 2016 - 19:03
#18
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

Somehow my iPad is in war with the forum software ... :-(

Starboard forward frame again. Sorry. 

 
     
 

 
     
 
 
04 April 2016 - 12:44
#19
 
  the professor Join Date: 02 January 2008
Posts: 1148
 
 

Dear Christian

You were really fortunate, a close call indeed...
Would like to ask if the fire was 3 m from the rig without anything in between or cooling with water? If the rig heated up this could be detrimental.
 
The internal bottom structure looks fully in order, and spotlessly clean as always.
Would suggest the outside laminate at the trailing edge be replaced if you are concerned about the cracking. Dig out until intact laminate is found, and use double bias stiched fabric laid alternatingly at 0/90 and +45/-45 with epoxy resin, preferably using vacuum bagging.
Kind regards
Lars
 
     
 
 
04 April 2016 - 18:13
#20
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

Sear Lars, 

 

many thanks again for your professional advice. Good to know that the situation is OK. I think I will wait for IHe who offered to measure the radius on this aft keel edge, so I can have this repair done to at least the original thickness, better a bit more. 

No worries, my mast is OK. There are (were) two wooden buildings side by side. 1m of space between them. One burned down, the shipyard wood storage. The other - the mast storage shed - was flooded with water, execessively and over hours, by the fire brigade (but only after we told them to do so !!!). I had a look insides the building while they did this, and the rig did definitely not overheat. Will have a look again next weekend, but I am sure it is OK. 

Thanks, and all the best! Will now send some photos on the shaft strut thread. 

 

Christian

CHINOOK // 431-003

 
     
 
 
11 April 2016 - 22:01
#21
 
  Chinook Join Date: 17 March 2010
Posts: 48
 
 

Dear Lars, 

 

one more question. The boat has had this keel aft end crack for many years. I talked to my service shipyard today, it seems they can't do a repair job this spring. As I had said, they just burned down, and don't have time, recources and capacity right now. 

Would you think I can postpone this repair to autumn? Or do you feel this requires to be done before launching the boat again? I know this may be a difficult question.

 

Christian

CHINOOK // 431-003

 
     
 
 
 
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